Toe spring correction attachment for last lathes



April 18, 1939. G. CLAUSING *ww*2,154,726`f",

TOE SPRING CORRECTION ATTACHMENT FOR LAST LATI-IES Filed Nov. 14, 1936 4Sheets-Sheet l ATTORNEYS.

April 18, 1939- G. cLAUslNG 2,154,726

TOE SPRING CORRECTION ATTACHMENT FOR LAST LATHES Filed NOV. 14, 1936 4Sheets-Sheet 2 INVENTOR.

Egeo/@ C/aaS//gg ,49 www Apri] 18, 1939- l G. cLAUslNG 2,154,726

TOE SPRING CORRECTION ATTACHMENT FOR LAST LATHES JNVENToR. GeorgeC/aaS/'ng me S A TTORN-EYS.

April 18, 1939- G. cLAUsING 2,154,726

TOE SPRING CORRECTION ATTACHMENT FOR LAST LATI-IE5 Filed Nov. 14, 1936 4Sheets-Sheet 4 INVENTOR. G e orge C/ous/ng A TTORNE YS.

Patented Apr. 18, 1939 UNITED STATES PATENT ,OFFICE TOE SPRINGCORREGTION ATTACI-EMENT FOR LASTLATHES George Clausing, Portsmouth,Ohio, aSSignor to Vulcan Corporation, Portsmouth, Ohio ApplicationNovember 14, 1936, serial No. 110,794 4 Claims. (ol. 142-15) Thisinvention relates to last lathes and partion in a horizontal directionwill be relatively ticularly to improvements therein which functionlgreat while the amount of increase at the surface to change the normalpantographic operation of of the sole is relatively smaller. It willalso be the grading means incorporated in the lathe. found that thedimensions of the upper or comb 5 Broadly stated, the improvementreferred to is section vary but little, except that the comb is relicapable of correcting undesirable contour changes atively higher in theD width. Obviously, there-i .in a last which have been introduced by thewidth fore, a true pantographic enlargement in these and length gradingmeans when producing a width dimensions does not fullill therequirements series of lasts larger or smaller than a model last forwidth grading. This discussion is not infrom such model last. Suchcorrection may well tended to set forth rigid rules in the design of thel0 be the correction of improper toe spring in the model lasts, but topresent a general comparison last produced. In'anotherof its aspects,the imof the usual characteristics of lasts in various proveme'nt iscapable of adapting the produced widths. lIt is intended to laythe basisfor a delast to a shoe heel of different height than that scription ofthe manner in which a copying lathe l5 to which the model last isadapted. functions when grading upwardly or downwardly l0 It is withinthe normal capability of a copying from a model of 'a given width toproduce a last lathe to reproduce a three-dimensional object in ofgreater or less width. its original dimensions and contour with a highIt is obvious also that the model makers` ref degree of accuracy. Thatis, with an accuracy quirements will not be fulfilled in producing a 4Dzo commensurate with the usual accuracy required from a 4B by adding alayer of uniform'thickness 20 in the making of the last models. A verydifto every portion of the area of the model. As will ferent problem ispresented, however, when the appear hereinafter, not .only is suchactidn of the model is to be reproduced. in a proportionately latheundesirable, but the lathe cannot accurately larger or smaller size. Insuch instances, the produce such an effect. For purposes ofilluspantographic amplifying and reducing means tration, let the last bedivided into a plurality 25 found upon the lathe does not reproduce alast oi thinflat superposed layers, each layer being in the desireddirect proportion, and the probf disposed in a plane substantially atright angles lern of correctly grading a series of lasts vfrom a to theturning axis. During the turning operamodel according to the requiredsizes, widths, tion, the width grading means'on the lathe inheel heightand toe spring is a complicated one. creases the dimensions of each ofthese super- 80 Those requirements which relate to corrections posedlayers in direct proportionto the distance in heel height and toe springare incorporated in of their outline from the turning axis. lThis dithisinvention. rect proportional characteristic of the lathe pro- As apreliminary discussion leading up to the duces an acceptablereproduction of each of these particular problem with which the presentinvenassumed layers when grading from one Width to 35 tion is concerned,a general statement will herein another'at the heel and toe extremitiesof the be set forth pointing outarequirement for produclast. Whenturning at and adjacent the ball ing a correctly graded series of lasts.By way of and waist section of the last, however, an undeillustration,l'et it be assumed that a cross-secsirable relativeshifting of thelayers takes place 4o tion be taken of a model last at right angles towhich results in incorrectly reproducing the toe 4o its turning axis andat the ball portion thereof, Y spring and heel height of the last. Thepresent for example, in a 4B size. 'Ihis cross-section inventionprovides means for correcting toe will display the correct contour toinsure corspring and heel height, and by the same means, rect t in theshoe manufactured thereon, beother i.variations in the last may beintroduced,

cause the model has been fashioned correctly by such as a requiredchange in heel 4`height from 45 the vmodel maker. For comparison, let itnow that of themodel. It will be understood that the be assumed that across-section is made at the application of the principles herein setforth apball portion of a correct last in a 4D size. ply not only tograding from one width in a given Such a cross-section will be generallylarger size to another width in the same size, but also 5o in area thanin the B width model. This crossto any increase in width whether it bein the 50 section, however, will exhibit characteristics same size or indifferent sizes. which depart from a figure which has been en- It isevident in a ladys last, that the sides and larged in direct proportionfrom the cross-section bottom of the ball section are located farthestof a last of B width. For instance, it will be from the turning axiswhich is normally through found that the increase in width at the ballsecthe center of the last from heel .to toe. This be- 55 ing so, thewidth grading mechanism upon the lastlathe increases this distance fromthe axis in greater proportion than it does elements at other sectionsalong the last, for instance, atland adjacent the heel and toeextremities, these last named sections being closer to theturning axisof the last. In reproducing the model, therefore, the last lathe bendsthe ball. portion of the produced last downwardly to such an extent thata correction must be made therein, in order to turn a last having thesame heel height as the model. In other words, the layers, abovereferred to, are shifted one upon another an excessive vamount at andadjacent to the ball section. This bending of the last or shifting ofthe layers decreases to practically nothing at the heel and toe'extremities. Obviously, the contour of the last bottom is therebycaused to .deviate from the standard requirement set up by the modelmaker.

Attempts are made in various ways to correct this distorted modeling ofthe reproduced last. One method of correcting this excessive bending ofthe last is by what is known as the wedging process. To do this, a sawcut is made substantially in the 'plane of the ball of the lastextending from the top of the last to a point approximately 1/2 of thedistance to thelast bottom. .A V-slot is then cut upwardly from the lastbottom to a point closely adjacent the bottom extremity ofthe saw kerf.The toe part is then bent downwardly with relation to the heel part anda properly fitted wedge proportioned to insure the desired amount ofcorrection in the toe spring is cemented in place in the saw kerf, whichhas been opened by the bending of the toe. This wedging of the toecauses an angle of incorrect dimensions on the heel. To correct thewedge angle of the heel, it is wedged in the same general manner as thatof the toe, but in the opposite directionwith the Wedge atthe lastbottom. y This last mentioned practice is inaccurate and generallyunsatisfactory. 'I'he model maker lestablishes a denite shape for thesole line of a correct last which must conform to an accurate template',and the wedging of the last, as above described, does not produce a lastconforming -to the model makers requirements.

Furthermore, the wedging operation cannot change the curved contour ofthe instep to conform with the conception of the should be. l

It is one object of the present invention to provide means forautomatically reshaping the prole of the sole line of a reproduced last,either to conform with the model or to depart from it in a.vpredetermined manner. l

A further object of the invention is to provide means for automaticallycorrecting the toe spring of a series of lasts of various widths andsizes from a correct model.

Another object of the invention 'is\to provide means for varying thecontour'of a last in accordance with a determinable controllinginstrumentality such as a cam or other pattern means.

A further object of the invention is to provide means for bodilyshifting a'model last laterally of its thereby temporarily to move itsturning axis out -of alignment with the 'axis of the shaft which rotatesthe model, such movement taking place in predetermined amounts and intimed relation to the progress of the turning operation.

Another object of the invention is to provide model maker-of what thatcurve i the super-structure in a machine of the above indicatedcharacter, a positive stop means for accurately determining when themodel last is in its normal, axial or rest position.

A still further object of the invention is` to provide means whereby theheel height of a reproduced last may be varied from that of the modellast as desired.

Another object of the invention is to provide l mechanism for shifting amodel dog laterally of its axis, such mechanism being uneffected by therelative lateral motion between the axis of the model andthe modelwheel, thereby insuring that the modification or correction specified by.the model maker will be accurately applied.

A further object of the invention is to provide a mechanism forcorrecting or modifying a last produced from a model, such mechanismbeing readilyapplied to existing-lathes with practically f\ -In thedrawings,

Fig. 1 is a front elevation of a last lathe embod'yng the invention.

Fig. 2 is an enlarged end elevation of a portion of the latheillustrating those elements which constitute the invention. l

Fig. 3 isa front elevation vof the elements illustrated in Fig. 2.

Fig. 4 is a cross-.section axially through the model driving and holdingdog.

Fig. 5 is a cross-section through the model driving andholding dog in aplane at right angles to the section taken in Fig. 4.

Fig. 6 is a detailed view of the construction of the width gradingmechanism inorporated in the lathe.

Fig. 7 is a diagrammatic outline view illustrating the correction oralteration of a graded last.

Fig. 8 is a view of a modifled form of a model heel dog shifting cam. i

Figs. 9, 10, 1l and 12 shaping cams. 1

To present a complete and readily understood conception of theinvention, 'the following detailed description will'be based upon aparticular embodiment thereof.

The drawings illustrate the type of last lathe having a swing frame forrotatively supporting the model and last block. however, that theinvention may be applied to other types of last lathes. 'I'he swingframe l is pivotally supported at points 2 and 3 upon illustrate methodsof between the heel dog the heel dog 1 movable laterallyof the` turningaxis in a manner to be hereinafter -set forth. Such dog 'l is rotated bya shaft 9 journaled in the swing frame and driven by means of gearing,turning ax1s during the turning operation,

not shown, from a. shaftlllwhich is journaled in the swing frame and hasfixed upon its outer en d a pulley Il. by the heel dog I3 and a toe dogI4, both of which may be of usual construction, the heel dog I3 beinghere shown mounted upon the end of a shaft l5 disposed in axialalignment with the 4 of the main frame 5, and the model 6 is supportedin the swing frame l 1 and the toe dog 8 with The last block I2 isreceived It will be understood,

shaft 9 and driven from the shaft I0 by suitable gearing situated withinthe casing I6. The two dogs 1 and I3 are driven at synchronous speedeither in the same or opposite directions, depending upon whether aright or ay left last is being turned.

As a means for driving the shaft I0 and the-reby rotating the model andthe work, the pulley -II on the shaft I0 is driven by means of a belt'I1 which passes over the pulley II and also over a pulley I8 fixed upona short shaft I9 journaled in the super-structure 4 closely adjacent tothe pivotal point 3 between the swing frame I and the super-structure,(Fig. 1). Such shaft I9 has upon its opposite end a pulley over whichpasses a belt 2| and the belt 2I also embraces a pulley 22 xed upon ashaft 23 extending lengthwise of the machine and journaled at its endsupon the super-structure 4. The shaft 23 is driven from a motorsuspended from a bracket 25 fixed upon a shaft 26, the shaft beingjournaled in the main frame 5, and motor desirably is provided with avariable speed pulley 21 which drives a shaft 28 by means of a belt 29and a pulley3ll over which the belt passes. Such shaft 28 has xedthereon another pulley 3l over which passes a belt 32 which in turnpasses over another pulley 33 freely rotatable on the outer end of theshaft 23. 'Ihe pulley 33 has fixed thereto one member of a clutch 34,the other member of which is splined upon a shaft 23 and is axiallymovable into and out of engagement with the other clutch member by meansof a lever 35 fulcrumed upon the structure 4, which lever 35 may bemanually or automatically operated to engage or disengage the pulley 33with the shaft 23 thereby establishing or disengaging the drive from themotor to the model and last block.

Suitable means is provided for retracting and moving the respective toeengagement with the model 6 and block I2 thereby enabling insertion orreplacement thereof. Any usual means may be employed to accomplish thisend.

The Weight of the swing frame plus the necessary spring tension appliedin the usual or any suitable manner acts to maintain the model inengagement with the model wheel 36. Such model wheel is mounted upon acarriage 31 movable in a direction parallel to the axis of the modelupon ways 38 formed upon the main frame of the machine, and the carriage31 may be of usual construction and provided with a width grading slide39 movable horizontally upon the carriage in a direction perpendicularto the turning axis. The forward end of the slide 39 has rotatablymounted thereon the model wheel 36 and the other end of the slide 39 hasmounted thereon a` knife member 40 vertically adjustable with respect tothe slide (Fig. 4). Such knife member 40 engages the fan board 4I, whichis pivoted in the main frame of the machine at 42 and is of usualconstruction, the fan board 4I being oscillated upon its pivots in. itsusual`way by means of a link connection 43 adjustably pivoted at one endto an extension 44 o the fan board and at its other end to the sw' gframe at 45'.

In operation, the knife member 40 slides lengthwise of the fan board asthe carriage moves along its ways and is held thereagainst by a spring46 securednat one end to the slide 39 and at its other end to thecarriage 31. The fan board transmits motion to the slide andconsequently to the wheel 36 in proportion to the distance the knifemember 40 is adjusted away from chucks 8 and I4 intol the pivot points42 and also the extent of motion transmitted by the fan board isdependent upon the degree of motion of the swing frame as it movestoward and from the model Wheel. The vertical position of the knifemember 40 is adjustable by means of the screw 50 which is rotatablymounted upon the carriage 31 and is prevented from relative axialmovement therewith. Such screw 50 passes through the nut 5I upon theknife member 40 and as the screw is rotated by a hand wheel 52, suchrotation is transmitted through a shaft 53 and a pair of beveled gears54, orie of which is secured to the screw and the other of which issecured to the shaft 53. Means are thereby provided for readily raisingo r loweringr the knife member 40.

It is well known to those skilled in the last making art that theposition of the knife member with respect to the pivot points 42 of thefan board determines the degree of grade when width grading a last. Whenthe knife member is upon the longitudinal axis of the fan board no widthgrading is introduced. When, however, the knife is adjusted away fromthe axis of the fan board, oscillating motion of the fan board istransmitted to the model wheelthereby increasing or decreasing thetravel of the swing frame depend-A ing upon whether the knife member isabove or below the fan board axis. This motion of the model wheel addsto or subtracts from the width dimensions of the last which is beingturned from the block.-

The block I2 is modeled or turned by a rapidly rotating cutter 55preferably mounted on the shaft of a motor 56. Such motor is mounted ona carriage 51 which moves upon the ways 38 in a direction parallel tothe carriage 31. Preferably, the axis of the cutter is disposed at anangle to the axis ofthe block I2, thereby to provide room for the motorframe, with the axis of the model wheel also disposed at the same angleas the motor shaft.

The two carriages 31 and 51 with their relative speed modified bygrading means, and as the model is rotated against the model wheel. itis given a lateral bodily motion determined by its own contour. Itfollows that the swing frame and also the block I2 are given the samelateral motion. As the turning progresses, therefore, the model isreproduced in the block either in identical dimensions or as modified bythe width and length grading means.

To feed thecarriage 51 along the ways 38, the shaft 23 has securedthereto a step pulley 58 over which passes a belt 59 which, in turn,passes over another similar step pulley`;60 secured to a short shaft 6Ijournaled in a bracket 62 rigidly secured to the main frame. Such shaft8| has mounted thereon another pulley 63 over which passes a belt 64,which, in turn, passes over and acts to drive a pulley 65 which issecured to a shaft 66 journaled at one Such bearing 61 is pivoted to asupport to permit angular movement of the shaft 66, the shaft 66 beingjournaled at its other end to the bearing 68 which is movablevertically. The shaft 66 has secured thereto a worm 69, which engages aworm. gear 10 keyed to a shaft 1I journaled in the main frame. Suchshaft 1I has xed thereon a spiral gear 12 meshed with a similar gear 13mounted upon a short vertical shaft 14 journaled in the main frame andhaving a pinion 15 secured upon its upper end and engaging with a rack16 fixed to the carriage 51. Rotation of move in unison the length endon a bearing 61.V

That position which the block male dovetail the Worm 69 causes thecarriageV along the ways 38,. vAny desired employed to move the bearingthereby to engage and disengage from the gear 18 thus starting and feedof the carriage. l

Travel movement of the carriage 51 is transmitted to the carriage 31 bymeans of the length grading bar or the lever 18 and the link 19, whichis pivotally connected to the carriage 51 at 80 and at its other end itis pivoted upon a block 82 adjustable lengthwise upon the upper end ofthe grading lever 18. The lever 18 is pivotally connected to thecarriage 51 at83 and the lower end of the lever` 18 is fulcrumed upon ablock 84 which is adjustable along a slot 86 in the lever.

As usual in this type of last lathe, the increment of length added to orsubtracted from the model length in a produced series of lasts isdetermined by the position of the block 82 with respect to thev pivotpoint 83. Such block 82 is held in adjusted position by a clamp 85. Foreach size of model that is employed in producinga series of lasts thefulcrum point of the grading lever must be situated in a deniteposition. 84 must assume for each model size is marked upon a rigid bar81 along which the block slides and to whichit is secured during theturning operation. The elements thus far described are or may be ofusual construction and it will be understood that other forms of lastlathes are adaptable to the principles of the present invention.

In accordance with this invention, the supporting member for the heelchuck or dog 1 comprises a head 88 which desirably has formed therein atapered hole 89 within which is received the tapered end of the lathespindle 9. 'I'he head 88 desirably is secured to the spindle by means ofthe key 90 and the head 88 is generally cylindrical in shape at itsinner end and has a collar 9| slidable axially thereon. Such collar 9|has a peripherial groove 92 therein, within which is re- 56 to be fedmeans may be 68 vertically, the worm 69 stopping the ceived a ring 93which embraces the collar, and

desirably, is composed of two semi-circular sections bolted together bythe bolts 94. Oppositely disposed trunnions 95 project outwardly fromthe ring and are received within a pair of blocks 96, which in turn, areslidably received in slots 91 formedin the ends 98 of a forked lever 99.The lever 99 moves the collar 9| axially along the head 88 in a mannerand for a purpose to be set forth hereinafter.

'I'he end of the head 88 adjacent the model is provided with adovetailed groove v extending at right angles to the axis of the spindle9. A

|80 and is integral with adog supporting slide |02 and the slide |82 hasfiat-faces |03 which engage with fiat faces |84 on the head 88. Thus,the thrust occasioned. by the clamping of the model between the heel andtoe dogs is taken up by the substantial area existing between the fiatfaces |03 and |84, which, when properly lubricated provides reasonablyfree action'of the slide |02 with respect to the head 88. The end of theslide |82 adjacent the model is slotted to receive a tongue portionformed on the dog 1, which dog desirably is pivoted to the slide'bymeans of a pivot pin |06 thereby to enable the dog to seat rmly againstthe back of the heel.

'I'he end'faces |01 of the slide |82 are parallel and disposed at anangle of substantially 27 with respect to the axis of the spindle, theangle being |8| is received within the groove l .|3| of the lever has ofany suitablel degree depending upon the amount of motion desired in theslide |02. One of the end faces |81 is engaged by a cam member |08 xedlymounted by means of a screw |09 within a slot ||8 in the collar 9| andsuch cam member |08 has sucient depth to project into a slot in the head88 and is slidably received therein. This cam member |08` forms a splinebetween the head 88 and the collar 9|. The end of the cam member |08adjacent to the model has a cam face 2 disposed at the same angle as theadjacent face 01 of the slide |82. Another cam member ||3 is secured inthe collar 88 in oppositely disposed relation to the cam member |88, anda slot 4 is formed in the bore of the collar within which is receivedthe cam member ||3. The end of this cam member 3 adjacent to the modelhas a cam face ||5 disposed at the same angle as the adjacent end face|81 of the slide |82.

The end of the collar 88 adjacent to the model desirably has formedtherein a rectangular opening ||6 through which the cams ject. Thejunction of lthe rectangular opening and the adjacent end of the slot||4 forms a shoulder |I1, while the other end of the slot ||4 has formedtherein a recess I8. As shown, the

outer face of the cam member ||3 is formed with projecting portionswhich fit over the shoulders |1 and |8 while the'inner face of the cammember engages the cylindrical portion of the head 88. 'Ihe cam member|3 is placed in position before the head 88 is inserted in the collarand when it is so inserted serves to retain the cam member in its properposition.

The two cam faces 2 and ||5 embrace the end faces |01 of the slide |82,and When the collar 9| is moved axially along the head 88, the slide |82moves at right angles to the axis upon which the head rotates by reasonof the cam action between the faces |01, ||2 and ||5. Since the dog 1 ispivoted to the slide |02, the dog also is moved laterally, carrying theheel it. The head 88 is recessed at |20 to .permit the cam ||3 to enterthe head when the collar 9| is retracted to its maximum amount. Thefacef`|2| of the dog 1 desirably is concave in form to con` form withthe contour of the back of the heel of the model and, as is usual, thisface is provided with sharp edge tines |22 which are forced into thewood of the model when pressure is applied at the toe dog.

An oil cup |23 is provided for lubricating all of the moving parts ofthe assembled dog shifting mechanism, the outlet of the oil cupcommunicating withA a peripherial groove |24 at the bottom of the groove92 in the collar 88. Thus, the surplus oil which accumulates in thegroove |24 flows through a drilled hole |25 and from this point acts`rto lubricate the bearing surfaces between the head and the collar andalso the sliding surfaces at the dovetailed connection between the headand the slide |02 as well as all of the cam faces. As above pointed out,the slide |02 is shifted laterally by movement of the lever 99 whichacts through the link 93 to move the collar 9| axially of the head 88.Such lever 99 is fulcrumed upon a block |26` rigidly secured to thehorizontal bar |21 at the lower end of the swing frame. The block |28 issecured in place upon the bar by means of screws |28 which pass throughplates |29 vand have screw threaded engagement with the block. The lever99 is pivoted to the block by means of a pivot pin |30. A horizontalarmpivoted to its outer end, a

end of the model with |88 and ||3 pro- .long link |32 which is pivotedat its other. en d lupon a substantially horizontal lever |33 at |34.

outer end of the lever |33 has pivoted thereto aty |31 a link |38 whichextends downwardly and has upon its lower end a clevis connection |39which embraces and is pivoted to a long horizontal lever |40 at |'4|.The lever |40 extends substantially the full width of the last lathe andis pivoted at |42 upon the main frame and the free end of the lever |40is guided vertically within a bracket |43 secured to the main frame.

As shown, the lever |40 is provided with a detachable cam |44 having acam face |45 which is engaged by a cam roll |46 rotatably mounted upon abracket xed to the carriage 31. Such cam |44 desirably is adjustablelengthwise of the lever |40, such adjustment being provided for by ascrew and slot connection |44X with the lever. As the carriage 31 isf'ed along the ways, the lever |40 will be moved in accordance with theshape of the cam face |45, and the motion of the lever will betransmitted to thev dog 1 through the link'l38, the lever |33, the link|32 and the lever 99.

Referring to Fig. 2, the pivot point |34 is situated in axial alignmentwith the pivot point 3 between the swing frame and the lathesup-erstructure when the collar 9| is at the mid point of its travelalong the head 88. A minimum movement is therefore given to the pivotpoint |34 away from its position of axial alignment with the pivot 3,and by thus coniining the pivot point |34 closely adjacent the pivotpoint of the swing frame, the function of the mechanism above describedfor moving the dog 1 is practically uneiected by movement of the swingframe during the turning operation.

Obviously, the cam |44, (Fig. 3) may be shaped to fulll the requirementsof any given problem. To further provide the operator with a means forestablishing and checking the operation of the device, the guide bracket|43 is provided with a scale |46, (Fig. 2) to the side of the guidingslot |41 within which the end of the lever |40 moves. By noting theposition of the leverwith respect to the scale, the operator maydetermine how much throw the cam is transmitting to the dog 1.Desirably, the scale should be calibrated to indicate known incrementsof motion of the dog 1.

The lever |40 and its cam |44 may be held 'against the roll |46 in anydesirable manner.

As herein shown, removable'weights |49 are suspended upon a rod |50. Therod |50 is suspended upon the lever |40 at |5|. The upward movement ofthe lever |40 is imparted thereto by the throw of the cam as thecarriage 31 moves along the ways while the downward movement of thelever is imparted by the weights |49.

It is highly desirable that the operator be provided with a ready meansfor returning the dog to its neutral position or that position whereinthe normal turning axis of a model when clamped in turning position isin alignment with the axis of the driving shaft 9. This may be efectedin any suitable manner and as herein shown, a stop pin |48 (Fig. 2) isplaced in an aperture in the plate |43 in correct position to stop thetravel of the lever |40 in its downward movement at the point where thedog 1 is in its neutral position. For operation of the machine requiringdownward motion of the lever |40 beyond this vpoint the pin |48 isremoved.

As previously pointed out, .the width and length grading means causeincorrect modeling of the 'last produced when grading' from one Awidthto another in the same size, or when grading from a 4 to a 6 size, whichautomatically requires a change in width of the last. The presentinvention functions to correct the error in the modeling of the lastwhich causes an incorrect toe spring and heel height. Briefly stated,the above de- -scribed machine accomplishes the correction by shiftingthe normal turning axis of the model away from the axis of the drivingspindle. By normal turning axis, is meant that axis upon which the modelis rotated in the lathe during a normal turning operation. To accomplishthe desired correction, the cam |44 is designed to give the propercorrective motion to the dog 1. Such a cam has a substantially straightportion |52 disposed at a small angle from the horizontal, the end ofthis portion |52 adjacent the heel dog being nearer to the lathe axisthan the other end. This straight portion connects with a convexlycurved portion |53, the high point of which determines the maximum throwof the cam and, in turn; connectswith a concave portion |54. Such caveportion of the cam causes a relatively rapid drop of the lever |40 andcauses the dog- 1 to smoothly return to the initial position, abovedescribed. Obviously, the correction accomplishes much more than thesimple wedging operation many times employed to crudely correct the toespring of a last as hereinbefore mentioned. The contour of every sectionof the last turned under the principles of the present invention ispredetermined and under the directA control of the model maker and thelathe operator by the simple expedient of designing a cam. A graphicillustration of certain of the corrections which may be made by thepresent invention are illustrated in Fig. '1. This figure illustrates inoutline 'a womans-last, showing in full lines the contour of a correctlast, for example, in a size 6B while superposed thereon and shown indotted lines is the outline of an uncorrected 6B last, graded from asize 4B model and in dash lines is shown the outline of a last which hasbeen turned and graded from an 8B to a 6B, for example, without'correction of the error introduced' by the width grading mechanism. Forillustration, a womans last was selected to be used in connection with arelatively high heel, such as a 21/2 or size 20/8 heel, since the errorcaused by width grading is more pronounced in a last of this type.

Referring now to the dotted line in Fig. '1, it will be noted that thebottom profile of the model has been bent downwardly at the ball sectionan appreciable amount, thus causing the angle which the sole line Amakes with the axis X-X of the' Thus, when the last repl v the ball anamount E; while as the turning operation progressed along the fore partfrom heel to toe, the dimension E is gradually decreased until the tipof the toe is reached where the width grading ampliiication ispractically COD.-

The angle of the sole line is thus distorted into an incorrect angle.Obviously, the error illustrated by the dotted line also is present,-when grading from a model of a given length and Width to a model of forifrom a large size model to a small size reproduction the dimension Dhas been decreased an amount E'. In this latter case, the angle betweenaxis A-B and the sole line G of the fore part has beenireduced. Whenthis last is placed in tread position, the line of the heel bottom willbe disposed in a position below that which it normally should assume,thus preventing a standardized heel from being placed in proper relativeposition to the last. The remedy is to increase this angle until it isequal to that of the model, as shown in full lines in Fig. 7.

The corrected motion of the model resulting from the action of the camduring the travel of the model wheel'throughout the length of the modelwill now be followed. At the start of the turning operation, the heelend of the model is deflected the maximum amount, so that the bottomsurface thereof is moved inwardly toward the rotational axis. Since theheel height and toe spring are to be corrected, it naturally followsthat theheel end of the model should have its maximum deflection at thistime. As the turning operation progresses, the roll |46 engages theportion. |52 of the cam which causes the model to approach its normalturning axis. Thus, when the point |53 is reached, the model wheel isengaging the model at the point X indicated-in Fig. 7,

which is a point slightly in advance of the forward end of the recess inwhich the heel plate of the last is secured. From this point, the roll|46 traverses the portion |54 of the cam which permits the lever |40 todescend smoothly and with the changing rate of deceleration therebytapering off the-corrective action of the cam until the end portion |55is reached when the lever will again be in the same positionas when theturning operation was initiated.

From this point in the turning operation, the cam is inoperative and theremaining portion of the fore part is copied with no shifting movementof the model. In the finished last thus produced,` the'depressed dottedoutline illustrated in Fig. 7 is moved upward to the correct full lineposition. The correct heel height and toe spring are therebyestablished.`One method of visualizing what has taken place during this correctiveturning operation is to assume that the last has been divided into aninfinite number of transverse planes or laminae. Let it now be assumedthat y these laminae have been shifted one upon another,

thereby to modify the contour of the bottom pro` ille of the lastaccording to a predetermined system introduced by the cam.

I t will be well to point out the adjustment which takes place in thewidth grading mechanism to bring about a reduction in width as comparedto an increase in width. As shown in Fig. 4, the knife member 40 issituated above the pivot 42. In this case, the width grading mechanismincreases thewidth of the last which is being turned, whereas, in theexample, which is at present under discussion, where it is desired toreduce the width of; the model in the last being turned, the knifeAmember 40 is adjusted to a position below the lpivot 42 of the fanboard.

To correcta last which ls reduced in width, it is necessary to design acam along the lines-of that shown in Fig. 8. y This cam produces motionsof the dog 1 opposite in direction and degree to that of the cam |44 atcorresponding positions of theI model wheel along the model. This camhas an angularly disposed portion |58, the left hand extremity ofWhichlis situated a correct distance with respect to the roll |46 tocause the heel dog l to assume its predetermined initial correctiveposition. 'Ihis portion |58 slopes upwardly in a v substantiallystraight- -line until it reaches the portion |59 of the cam Wheremaximum deflection of the dog 'l has taken place. At this point, theheel of the model has been shifted the necessary amount to cause thesole line reproduced in the block being turned to assume its correctposition so that when the last is placed in correct tread position, itwill receive a heel which it has been designed to receive. At this time,the roll 46 is` contacting the point X upon the model.

From the portion |459 of the cam, its face slopes downward with a smoothcurve until it reaches the portion, |60 of the cam. The portion |60maintains the rollI |46 in a fixed position throughout the remainder ofthe turning operation, such position being proper to produce the correctdeflection of the model from its vnormal turning axis to move theportion G of the sole face in the last produced from its incorrectposition shown in dotted lines, Fig; 7 to the correct position shown inthe-full line. The portion |60 of the ca'm is reached just as the modelwheel engages the ball portion ofthe last.

Itwill be noted that in each case, the dog moves the heel end of themodel only and that the deflection of the axis of the model from thelathe spindle axis is greatest a given movement of the cam end anddiminishes to .0 at the toe. Therefore', irrespective'of what thedeflection of the heel may be, all deflection will diminish to-Ogardless of the fact that the lever |40 will be held in its upwardposition by the portion |60 of the cam |51, the deflection of the dog 'lwill diminish to substantially 0 at the extremity of the toe when theturning has reached this point.

No mention has thus far been made ofthe contour of the upper portion ofthe last. The dotted line and the dash line illustrate respectively thecontour of the upper vportion of the last which is at the heel end forat the toe extremity. Re-` formed by the width grading mechanism withoutcorrection in the ilrst case when increasing the width of the model andthe second case when decreasing the'width of the model. It will be notedthat the outline of the comb has been raised a considerable amount inincreasing the width of the last. Such a change isdeSirable and producesa correct modeling in this part of the last. The contour in the portionVof the last from the top of the lcomb rearwardly to the heel is notcritical and no correctionv is necessary in` this part of the last."Along the upper surface of the fore part, the dimensions thereof areslightly changed. Such changes are, however, in the direction of actualcorrection rather than in the wrong direction and'the changes take placein substantially the proper proportion to produce a correct contour atthis'portion of the last.

template may then be plotted upon the cam, the

increments calculated in terms of the velocity ratio between the lever|40 and the dog 1.

A more practical method, however, is as follows: Assuming rst, a cam isto be designed to correct a last which is to be graded from a model of agiven size'to a last of -a diierent length but of the same widthdenomination. Such a cam is illustrated in Fig. 9 and is similar to andfunctions in the -same manner as the cam illustrated in Fig. 3. Thenecessary shift of the dog 1 from its normal turning position is firstdetermined at the initial position of the model wheel upon the model,which in this example, is at the heel extremity. From this amount ofshift, the dimension H., (Fig. 9) is calculated and extends from thecenter of the attaching screws for the cam to the left hand end of thecam face. This dimension is laid off on the cam blank. The dimension Jwhich is equal to the dimension H is cave portion at the then laid offat the right hand end of the cam blank.- v y v To obtain the correctcontour for the curved portions of the cam a shank template |6| is usedas a marking guide. A point I is now established at a distance J fromthe center of the attaching screws and ata measured distance K from theleft hand end of the cam blank. This dimension is properly determinedtov cause the roll |46 to reach the highest point on the cam when themodel wheel has reached the point X in Fig. 7. The shank template |6| isnow placed upon the cam blank at the low point of its conball endthereof coincident with the point I on the-cam blank. A straight edge|62 is then brought'into register with a portion N of the template whichis practically straight and extends towards the right from the highpoint thereof to a point near the heel end of the template. 'I'hestraight edge and the template are then moved together into suchposition that the straight edge registers with the point P at the lefthand end of the cam blank. A line is then drawn using the template andthe straight edge as a guide and the cam is cut upon this line. Thedistance Q thus determined will produce the correct maximum throw of thedog 1 at the point X on the model.

The correction introduced by this particular cam will correctly gradefrom a 4B to a 6B in a last having a specied heel height, for example, a16/8 heel. This cam is suitable for making the usual series of modellasts which includes every other size, for instance; a series includingsizes 4, 6 and' 8 in a B width, in which the 4 is used to make the 6 andthe 6 is used to make the 8. In turning this series, the cam must beshifted longitudinally of the lever |40 when changing from size to size.To do this, an arbitrary refer'- ence mark M is made upon the lever |40and a series of index marks' L are made on the cam to register with thereference mark M. These index marks are spaced the correct distance tolocate the high point R of the cam correctly for the last model sizeindicated.

To obtain a complete series vof models including width variations,another cam |63 is designed. `This cam is to have a much reduced throwasA compared to the cam |44, and is designed to effect the necessarycorrection when grading from a 4B to a 4C. 4The same general procedureis followed to design this cam as that employed inv designing cam |44. Acontour-'cuave |64,

shown in dotted lines and identical to the contour of cam |44, is firstlaid out upon the camV blank. The distance S which represents themaximum throw of the cam is measured. The de-v sired throw of the cam inthe'problem now under consideration is substantially 1/2 that of thetotal throw, represented by the dimension S. IThe-high point T of thecam now underl construction is laid off upon the cam blank measuringinwardly the distance 1/2 attaching screws from S toward the center lineof the the point R. From the high point thus determined, a smooth curveis drawn from the Point I to the high p oint T using the contour |64 asa guide for interpolating the points along the curve. 'I'he remainingcurved portion of the contour |65 is drawn in to smoothly meet thestraight portion U of the curve. Index marks L are then inscribed uponthe cam to properly locate its position along the lever |40. It

is abvious that a cam having any desired maximum throw may be designedby selecting the proper shank template and properly calculating l thedimensions above set forth.

The same general method is used in producing the cam |56 shown in Fig. 8as that which is employed to produce the-above describedcams.

This cam |56 is employed in cbrrecting the grading operation whichproduces, for example, a 2B from a 4B model. In this problem, the curveof the cam is concave instead of convex. The shank template |6| in thiscase is turned over so that its convexity extends upwardly. VThe lowpoint of the concave curve at the bottom of the template is placed upona point on the cam blank determined by the dimensions K and V. The

dimension V is found by calculating the necessary throw of the dog 1 toeffect the necessary correction, such dimension being transferred to thecam blank in terms of the necessary movement of the lever |40. Thedimension W is then laid ofi' equal to the dimension, since the startingposition of the dog is the same as its nal position. The contour curveof the cam |51 is then drawn by the aid of the in the same mannerdescribed in connection with the cam |44. The index markings L are theninscribed upon the completed cam.

The cam |66 shown in Fig. 12 is used for correcting a last which isgraded, -for example, from a 4B to a 4A size. In this cam, thedimensions V and W are used in the same manneras that employed todetermine the shape of the cam |51. .The extent of concavity in this camis less by substantially 1/2 than that of the cam |514. The contourcurve Y is then determined by using the curves of the cam |51 as a guidein the same general 'manner employed in calculatingthe curve of the camshown in Fig. 10. The index markings L are then marked on the cam. i

The cams shown in Figs. 9, 10, 11 and 12 represent. a `set which willenable the lathe operatorV to produce a seriesv of correct model lastsfrom a single model produced by the modelmaker according to a requiredstyle and heel height.

- as a template.

VHaving thus described the invention,'what is desired to be secured byvLetters Patent, is:

1. In a last lathe having model wheel and cutter carriages, means forrotatively supporting a model last comprising heel and toe dogsengagtemplate straight edge ing the ends of the model, a driven spindlefor rotating'the model and dogs, a free inner end on cam on said lever,a co-operating follower on one of the carriages of the lathe, and alever and linkage system for transmitting the movement developed by saidcam and follower to said sleeve and dog.

2. Alast lathe -having the elements dened in claim 1 together withyielding' pressure means `ior maintaining the cam secured to thelever inengagement with its co-operating follower.

3. A last lathe'having the elements defined in claim 1 together withyielding pressure means for maintaining the cam secured to the lever inengagement with its co-operati'ng follower and positive stop means fordetermining the initial position of the lever carrying the cam therebydetermining the initial position o1' the laterally movable dog.

4. In a last lathe having model wheel and cutter carriages movablerectilinearily of the lathe frame, a swing frame, a driven spindlemounted in said swing frame operable to rotate the model, aheaddetachably secured to the inner free end of said spindle androtating therewith, a dog for engaging the ends of said model, means insaid head for receiving and guiding said dog laterally of the spindleaxis, a sleeve slidable axially upon said head, cams upon the innerperiphery of said sleeve engaging and moving said dog upon axialmovement o1' said sleeve, a lever rextending parallel to the spindleaxis and fulcrumed on the lathe frame to swing in a vertical plane, aco-operating cam and follower, one of which is mounted on said lever andthe other on one of said carriages and acting upon Vmovement of thecarriage to actuate said lever, a link connected to said lever andextending substantially vertically upward, a second lever fulcrumed onthelathe frame adjacent the pivot of said swing frame, a pivotalconnection between said second lever and 'said link lying substantiallyupon a radial line from the swing -frame pivot to the axis .of saidspindle, and a second link connected at one end to said second lever andat its other end to a bell crank lever fulcrumed upon said swing frameand operable to move said sleeve.

GEORGE CLAUSING.

